Preparation of esterlike derivatives of vat dyestuffs



l poses, consistin Patented Sept. 3, 1929.

UNITED STATES MABCEL BADER AND CHARLES SUNDER,

VOLTZ, OF BASEL, SWITZERLAND, ASSIG S. A., 01 BASED, SWITZERLAND.

F MULHOUSE, FRANCE, AND THEODORE NOB/S TO THE FIRM DURAND & HUGUENIN PREPARATION OF ES'IEBLIKE DERIVATIVES 01 VAT DYESTUFFS.

Ho Drawing. Application filed July 27, 1923, Serial No. 654,273, and in Germany August 21, 1922.

The U. S. Patent No. 1,448,251'discloses a process for the manufacture of water-soluble ester-like derivatives of vat-dyestufis, especially valuable for dyeing and printing purin treatin the leuco-compounds of vatyestufis wit chlorosulfonic acid in presence of a tertiary base, that is a tertiary organic nitrogen-containing base with or without the use of an indifferent l0 diluent.

. is filtered hot. A small Now we have found that the chlorosulfonic acid can be replaced by sulfur trioxlde (S0,) as such or in the form of fuming sulfuric acid.

Example 1.

To a strongly cooled mixture of 120 parts of chlorobenzene, 90 arts of dimethylaniline and 26 parts of euco-indigo there are added, while stirring, with exclusion of air, drop by drop, 36 parts of fuming sulfuric acid of 66 per cent The mass is agitated for some time in the cold and thereupon brought slowly to 60 C. The agitation is continued until the end of the reaction. Afterwards an alkali is added and the dimethylaniline and chlorobenzene' are distilled ofi by introduction of steam. The residual solution quantity of indigo remains on the filter, while the solution is allowed to cool down in order to crystallize out the ester-salt. The latter is soluble in water and especially valuable for dyeing and printing; by means of a suitable oxidizing agent with acid the original dyestufi is reformed.

Example 2.-

Into a strongly cooled mixture of 120 arts of chlorobenzene and 48 parts of dimethy aniline there are introduced, while stirring, 24 parts of sulfur trioxide. During the operation the air is removed in the reaction vessel by carbon dioxide. To the resultin mixture there are then added'26 parts 0 leucoin igo. Themass is agitated for some time in the cold and then, while continuously stirring, heated slowly to 50'60 (3.. The further treatment takes place as in the foregoing example.

The body obtained robabl v corres onds to the formula: p y p OSOaX 080;)! 0 C whOTQln X represents hydrogen or metal.

If X stands for sodium, there is a sodium salt which is easily soluble in water.

The herein described modification of the process can be applied in the same sense and to the same extent as in the U. S. patent above referred to.

What we claim is:

1. A process for the manufacture of stable esterlike derivatives of vat dyestufis in solid form soluble in water, consisting in treating a leuco compound of a vat dyestuff with fumingsulfuric acid in presence of a tertiary organic nitrogen-containing base capable of promoting the esterification.

2. A process for the manufacture of stable esterlike derivatives of vat dyestuffs in solid form soluble in water, consisting in treating a leuco compound of a vat dyestufi with sulfur trioxide in presence of a tertiar organic nitrogen-containing base capable o promoting the esterification;

3. A process for the manufacture of stable esterlike derivatives ofvat dyestuffs in solid form soluble in water, consisting. in treating a leuco compound of a vat dyestufi with fuming sulfuric acid in presence of dimethylaniline.

4. A process for the manufacture of stable esterlike derivatives of vat dyestuffs in solid form soluble in water, consisting in treating a leuco compound of a vat dyestuif with sulfur trioxide in presence of dimethylaniline.

5. A process for the manufacture of stable esterlike derivatives of vat dyestufl's in solid form soluble in water, consisting in treating the leuco compound of indi o with fuming sulfuric acid in presence 0 a tertia organic nitrogen-containing base capab e of promoting the esterification.

6. A process for the manufacture of stable esterlike derivatives of vat dyestufis in solid form soluble in water,

consisting in treating the leuco compound of indigo with trioxide in presence of a tertiary orgamcm- 5 trogen-containing base capable of promoting the esterification.

7. A process for the manufacture of stable esterlike derivatives of vat dyestufis in solid form soluble in water, 0 the leuco compoun sulfuric acid in presence of consisting d of indigf with fuming in treating 'methylaniline.

trioxide in presence of dimet MARCEL BADER. CHARLES SUNDER.

THEODORE VOLTZ.

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